1. Field of the Invention
The present invention relates to a rubber/resin ultrasonic bonding method, and more particularly to a rubber/resin ultrasonic bonding method in which a bonding surface of a rubber member and a bonding surface of a resin member whose fusion point is lower than that of the rubber member are connected to constitute a bonding interface and the resin member is fused by friction heat generated by application of ultrasonic vibrations to the bonding interface from the rubber member side, so as to bond both the members.
2. Related Art
Conventionally, for example, when attaching a rubber member to a resin member, an affixing method using a pressure sensitive adhesive double coated tape and a resin pin crimping method in which a resin pin provided on a resin member is passed through a hole in a rubber member so as to be crimped at a distal end thereof have been in use.
In addition, a vulcanizing adhesion method is also known in which a bonding surface of a resin member is embossed when molding the resin member, so that a rubber member can be bonded to the bonding surface of the resin member so embossed when vulcanized (for example, refer to JP-A-5-99266).
On the other hand, although it is not a bonding method for bonding a rubber member and a resin member, an ultrasonic welding method is also known for welding a hard resin member and a soft member made of a thermoplastic elastomer of the same resin base as the hard resin member using ultrasonic vibrations (for example, refer to JP-A-2001-275751).
In this ultrasonic welding method, a bonding surface of a hard resin member made of polypropylene (PP) is connected to a bonding surface of a soft member made of a olefin based plastic elastomer having compatibility with PP and a Shore A hardness (JIS-A hardness) of 90 or greater so as to form a bonding interface, and both the members are fused by friction heat generated in the bonding interface by application of ultrasonic vibrations to the bonding interface from the oft member side, whereby both the members are fusion bonded by chemical bonding force generated by molecular bond.
The conventional methods have their respective problems as below.
Namely, in the affixing method using a pressure sensitive adhesive double coated tape, the production costs are increased by such an extent that the pressure sensitive adhesive double coated tape is used. In addition, since the adhesive double coated tape made of a different material remains on the bonding interface, there occurs a case to which this method cannot be applied.
In addition, in the resin pin crimping method, both the resin member and the rubber member need to be molded with high accuracy so that the thickness and position of the resin pin on the resin member can accurately match the diameter and position of the hole in the rubber member, this also leading to high costs.
Furthermore, in the rubber vulcanizing adhesion method, since the rubber member needs to be vulcanized for adhesion to the resin member while being vulcanized to be molded into a predetermined shape in such a state that the resin member, which has been molded into a predetermined shape in advance, is disposed at a predetermined position in a rubber vulcanizing and molding mold, a mold having a special and complex construction is necessary as the vulcanizing and molding mold, this also resulting in high mold fabricating costs.
On the other hand, in the ultrasonic welding method, this is really the method in which members of the same resin base which are compatible with each other are fused together so as to be fusion bonded by chemical bonding force, and a rubber member and a resin member cannot be bonded by this method.